This invention relates to apparatus and a method for laminating patches of a first web material onto a larger web of a second web material. More particularly, this invention relates to apparatus and a method for laminating patches of web material onto cigarette paper prior to the incorporation of the cigarette paper into cigarettes.
Cigarette papers have known burning characteristics, including burn rates and static burn capabilities. It is known that such characteristics can be modified by adding fillers and burn control additives to the papers. It is also known that such characteristics can be modified in selected portions of a cigarette paper web by applying to the web a strip or patch of a paper having different characteristics than the web to be modified.
For example, it is shown in copending, commonly-assigned U.S. patent application Ser. No. 07/605,402, filed Oct. 30, 1990, which is hereby incorporated by reference in its entirety, that cigarette wrapper paper can be modified in periodically spaced areas by applying bands of a different paper at periodically spaced positions across the width of the wrapper paper, so that cigarettes produced from the wrapper paper have periodically spaced circumferential bands on the inside of the wrapper for modifying the burning characteristics of the wrapper and the cigarette. One treated paper material suitable for forming the periodically spaced bands is described in U.S. Pat. No. 4,739,775, which is hereby incorporated by reference in its entirety.
The application of bands to a base cigarette paper web can be accomplished "on-line" on a cigarette making machine, by adding one or more stations to the machine between the cigarette paper unwinding station and the garniture of the machine. However, the cigarette paper is moving at very high speed (e.g., up to about 700 m/min) at that point and it may be difficult to control the proper placement of the bands. For example, it may be difficult to line the bands up as nearly perpendicular to the paper edge as desired, or to line up the bands with the paper edge without overlap. It may also be difficult to assure that the bands are firmly adhered and set by the time they reach the garniture, so that they do not move during cigarette formation. To the extent that these difficulties may arise, it may be advantageous to laminate the bands to the cigarette paper in an "off-line" process where it may be possible to better control the placement and adhering of the bands. It would also be advantageous to be able to laminate the bands to the cigarette paper with better control even on-line on a cigarette maker.
It would be desirable to be able to provide apparatus and a method for laminating patches to a base web accurately, and as efficiently as possible.